Twitter has cracked down over online infringement of the Olympic logo after the Games' organisers, Locog, complained that an activist group had used the trademark 2012 image to parody the London sporting festival.

A week after Space Hijackers set themselves up as the "official protesters of the London 2012 Olympic Games", Twitter suspended the account without warning, saying the satirists' use of the logo as a Twitter picture was an abuse of its rules as it meant they could be "confused" with an actual Olympic sponsor.

In correspondence with the group, Twitter is understood to have written: "We have received reports from the trademark holder, London Organising Committee of the Olympic Games and Paralympic Games Ltd [Locog], that your account, @spacehijackers, is using a trademark in a way that could be confusing or misleading with regard to a brand affiliation. Your account has been temporarily suspended due to violation of our trademark policy."

The group says that after it wrote to Twitter, the account was unlocked late on Wednesday afternoon and it had been given 48 hours to comply with Twitter's orders or face having the account, with its 2,700 followers, permanently suspended.

A spokesman for the group who used the name "Bristly Pioneer" said he was surprised at Twitter's decision. "Our latest project is to do with the Olympics and obviously they have got an official chocolate bar and an official TV and the rest of it and we thought what they were missing was an official set of protesters," he said.

"We were kind of surprised that Twitter, after having supported everyone through the Arab spring … shut down our account without even asking any questions … they locked us straight out of the account, no questions."

The group, who once tried to sell a tank at a UK arms fair, said it was clearly not trying to sell "fake tickets to the Games" and that what it was engaged with was "purely social commentary".

"These trademark laws are set up so that Pepsi don't infringe on Coca Cola's branding. It is not set up so Locog can stamp down on a school fete because they've got some Olympic rings on their iced buns."

The spokesman added that the group had had "instant support" including from the comedian Mark Thomas, who changed his Twitter avatar to that of Space Hijackers' redesigned Olympic logo in anarchist black and red.

Pioneer also described the logo as a "social meme" that had become part of the London landscape. However, despite its ubiquitous presence, he said, it could not be used by ordinary people. "It's like Voldemort – you're not allowed to mention it otherwise you'll invoke the wrath of Locog."

Locog said it had complained to Twitter using normal channels open to any member of the public.

A spokesperson added that Locog was not taking issue with Space Hijackers' politics: "This is purely about our logo."